1. Field of the Invention
The present invention relates to a display apparatus, and more particularly, to a display apparatus capable of indicating a picture-in-picture (PIP) function on a color display tube (CDT) monitor.
2. Description of the Related Art
With a jump to a higher level of information society, multimedia systems have rapidly come into wide use. Accordingly, the importance of display devices functioning as a bridge between human beings and electronic devices has increased.
Analog signals have been generally used when displaying a signal from a personal computer (PC) or television/video through a CDT monitor system. As shown in FIG. 1, a signal from a PC 10 is amplified by an amplification unit 11 and is displayed on a CDT 12 monitor such as a cathode-ray tube. On the other hand, digital data must be used when a signal from the PC or television/video is displayed through a liquid crystal display (LCD) monitor system.
In order to realize the PIP (picture-in-picture) function of indicating at least one sub-screen together with one main screen at the same time, as an optional function of a monitor, a signal from a PC or television/video must undergo a digital signal process. Therefore, the PIP function can be more easily realized in the LCD monitor than in the CDT monitor. To realize the PIP function in the CDT monitor, a scaler integrated circuit (IC) that is used in the LCD monitor is needed. However, when the scaler IC is used, a signal is displayed on the CDT screen after being converted into a digital signal, processed with a PIP process in the scaler IC, and then converted back into an analog signal. During these processes, screen image quality may be degraded.